The mishap took place when the victims were returning to to Tarn Taran district in Punjab after paying obeisance at Dera Baba Vadbhag Singh shrine in the bordering Una district, Deputy Superintendent of Police Madan Lal said.
The injured were admitted to the district hospital at Una, he said.
According to the police, the truck was converted into a double-decker by fitting wooden planks so that more passengers could be accommodated and eye-witnesses said that there were more than 60 people travelling in the ill-fated vehicle.